Magnetic refrigeration technology at ambient temperature has been known for more than twenty years and the advantages it provides in terms of ecology and sustainable development are widely acknowledged. Its limits in terms of its useful calorific output and its efficiency are also well known. Consequently, all the research undertaken in this field tends to improve the performance of such a generator, by adjusting various parameters, such as the magnetization power, the performance of the magnetocaloric element, the surface for heat exchange between the heat transfer fluid and the magnetocaloric elements, the performance of the heat exchangers, etc.
One of the difficulties in the realization of generators that use one or more magnetocaloric elements lies in the exchange of thermal energy between these magnetocaloric elements and the circuit(s) that use, consume or exchange the thermal energy with the generator, and that are connected with the latter. A solution for performing this exchange consists in making a heat transfer fluid, liquid or not, circulate through the magnetocaloric elements, in synchronization with the variation of the magnetic field which the magnetocaloric elements are subjected to and to perform then a thermal exchange between the heat transfer fluid and the circuits.
The publication WO 03/016794 gives an example of implementation in which the magnetocaloric elements are in a closed fluid circuit including a circulation pump for the heat transfer fluid, located outside of the thermal module and requiring specific control and connection means.
In the French patent application no. 07/07612, the applicant presents a heat generator with magnetocaloric material in which the heat transfer fluid is circulated between the magnetocaloric elements and two exchange chambers called a hot chamber and a cold chamber. This circulation is carried out by means of two sets of pistons that are positioned opposite the magnetocaloric elements and driven by a control cam connected to an actuator.
This generator nevertheless has a disadvantage related to the need for two cams to drive the two sets of pistons positioned opposite each magnetocaloric element. This leads to an increase of the number of parts making up the generator, and more specifically of the number of moving parts and thus to an increase of the risk of malfunction, to a higher risk of wear due to the permanent contact between the cam and the pistons, and to a degradation of the efficiency of the generator. Furthermore, the high number of parts also increases the space requirement of the generator and thus limits its ability to be integrated in environments in which the available space is reduced and limited.